Nurse sharks range in length from about 75 centimeters for the short tail nurse shark to 4 meters in length for the other types of nurse sharks. The average weight of a 240 centimeter long nurse shark is 330 pounds. They are generally dark in color or have dark scattered spots along their bodies. They have broad heads, no grooves around the outer edge of their nostrils, and relatively fat or stout bodies and tails. Their anal fins are slightly behind their second dorsal fins and just in front of their caudal fins. Anal fins are absent in some families of sharks.
Average mass: 60280 g.